Solid state illuminator for bi-colored ported water level gauges

ABSTRACT

A solid state illuminator and display means are provided for bi-colored ported water level gauges suitable for use in high pressure steam drums or similar water/steam devices to facilitate making an accurate determination of water level in such a device. The illuminator comprises an array of bi-colored solid state light emitting diodes (LEDs), as the light source, and a precision lens to focus the light provided from the LEDs through a gauge body and onto the view screen.

CROSS REFERENCE TO RELATED ART

This application is a national stage entry of PCT/CA03/01684 Nov. 03,2003.

FIELD OF THE INVENTION

The present invention relates, generally, to a device for accuratedetermination of water level in a high pressure boiler drum or othersimilar water/steam apparatus. More specifically, the present inventionutilizes an array of vertically arranged, bi-coloured, solid state lightemitting diodes (LEDs) to provide light that is focussed through anarray of precision lens and projected though either steam or water anddisplayed upon a view screen. The presence of either steam or water at alevel corresponding to each LED in the array of LEDs will result in aclear and unmistakable colour change observable on the view screen.

BACKGROUND OF THE INVENTION

The design and use of bi-coloured light for determining water levels insteam boilers is well taught and documented in the art. Traditionally,incandescent light is passed through coloured lenses as the lightsource. These designs suffer from numerous deficiencies in theirfragility, efficiency, power requirements and life span. An incandescentlight source utilizes a fragile filament operating at high temperature.This filament can easily become damaged and break when subjected tocontinued vibration. In addition, the high operating temperature of thefilament limits the life span of the incandescent light. The sameincandescent light source requires a high level of power to operate andonly a small percentage of this power is converted to usable light. Theremaining power is lost, predominantly as heat.

Numerous liquid level indicators can be found in the art to which thepresent invention provides advances. U.S. Pat. No. 2,510,729 describesan indicating gauge in which a vertical column containing both water andsteam includes a multitude of bores which pass horizontally through thecolumn and allow for visual inspection of the contents of the columnpresent at the corresponding level. An operator is able to inspect anddetermine the level at which the contents of the column shift from waterto steam.

In U.S. Pat. Nos. 2,024,815 and 2,115,889, indicators that utilize thereflective and refractive properties of water, steam and light arerevealed. In each case, the operator inspects the individual gaugeswithin a plurality of gauges and is able to determine the water/steamlevel by observing a colour change associated with the levelcorresponding to the change from water to steam. The device of U.S. Pat.No. 2,115,889 provides an additional means to visually inspect the gaugeat a greater distance, more specifically, at a position located farbelow the gauge. The light is provided in each of these devices via anincandescent light source.

U.S. Pat. No. 4,836,022 describes a bi-colour fluviograph for use insteam boilers and provides improvement to the intensity of lightprovided from the light source and includes benefits aimed at reducingthe frequency of maintenance of the fluviograph. The light is providedby a flourescent lamp and the colours are introduced via a two planes,one painted red, and the other green. The fluviograph increases theintensity of the red light to allow for its operation in murky orturbulent water conditions that would render most previous devicesinoperable. A further advantage is that the device need not be cleanedas frequently. Traditionally, the impurities in the water containedwithin the boiler would deposit on the lens and gradually reduce theeffective light transmitted. This effect is lessened by increasing thelight intensity.

SUMMARY OF THE INVENTION

The present invention provides a gauge system that incorporates a solidstate illuminator and corresponding view screen, which can helpaccurately determine the water level in steam boilers or similardevices, and do so in a safe, economical, and efficient manner.

The use of light emitting diodes as a light source in a level gaugeilluminator provides reduced operating costs in that much or virtuallyall power is converted to visible light. In addition, the nominal lifeof an LED is 100,000 hours. An LED is unaffected by continued vibration.An LED is capable of producing red and green light directly, eliminatingthe need for coloured glass. Finally, an LED requires minimal power tooperate and the use of a solid state illuminator would be intrinsicallysafe in a hazardous environment.

According to an aspect of the present invention, there is provided abi-colour ported water level gauge for use in determining the waterlevel in a steam/water environment, for instance in a boiler steam drumcomprising: an electronic printed circuit board containing an array ofhigh-intensity, narrow beam, red/green light emitting diodes; theelectronic printed circuit board being mounted on an electronics dividerboard; a divider board comprising a plurality of viewing ports, saidports being individually aligned with the light emitting diodes, andpreferably substantially equal in number thereto; a heat divider forprotecting the printed circuit board from high temperatures existing atan external housing comprising rows of offset slots to reduce heattransmission; and display means, such as a view screen, onto which lightoriginating from the light emitting diodes is projected for inspectionby an operator.

According to another aspect of the present invention, there is provideda bi-colour ported water level gauge illuminator for use in determiningthe water level in a steam/water environment, for instance in a boilersteam drum comprising: an electronic printed circuit board containing anarray of high-intensity, narrow beam, red/green light emitting diodes;the electronic printed circuit board being mounted on an electronicsdivider board; a divider board comprising a plurality of viewing ports,said ports being individually aligned with the light emitting diodes,and preferably substantially equal in number thereto; and a heat dividerfor protecting the printed circuit board from high temperatures existingat an external housing comprising rows of offset slots to reduce heattransmission.

According to an aspect of the present invention, there is provided abi-colour ported water level gauge for use in determining the waterlevel in a steam/water environment, for instance in a boiler steam drumcomprising: an electronic printed circuit board containing an array ofhigh-intensity, narrow beam, red/green light emitting diodes; theelectronic printed circuit board being mounted on an electronics dividerboard; a lens divider board comprising a plurality of viewing ports,each containing means, such as a plano-convex lens, for focussing lightoriginating from the light emitting diodes, said ports beingindividually aligned with the light emitting diodes, and preferablysubstantially equal in number thereto; a heat divider for protecting theprinted circuit board from high temperatures existing at an externalhousing comprising rows of offset slots to reduce heat transmission; anddisplay means, such as a view screen, onto which light originating fromthe light emitting diodes is projected for inspection by an operator.

According to another aspect of the present invention, there is provideda bi-colour ported water level gauge illuminator for use in determiningthe water level in a steam/water environment, for instance in a boilersteam drum comprising: an electronic printed circuit board containing anarray of high-intensity, narrow beam, red/green light emitting diodes;the electronic printed circuit board being mounted on an electronicsdivider board; a lense divider board comprising a plurality of viewingports, each containing means, such as a plano-convex lense, forfocussing light originating from the light emitting diodes, said portsbeing individually aligned with the light emitting diodes, andpreferably substantially equal in number thereto; and a heat divider forprotecting the printed circuit board from high temperatures existing atan external housing comprising rows of offset slots to reduce heattransmission.

A further aspect of the invention provides a method for determining thewater level in a boiler steam heater, or similar water/steam devicecharacterized by the steps of: projecting a first light from one or morelight emitting diodes of a first colour; projecting a second light fromone or more light emitting diodes of a second colour; passing said firstand second lights though a column containing steam and water at avarying level onto a projection screen positioned on an opposing side ofsaid column relative to said light emitting diodes; observing theposition of the first and second light on the projection screen atvarying vertical levels along the column; and determining the presenceof water or steam at each of said varying vertical levels based upon theobserved positions of the first and second lights on the projectionscreen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a perspective view of a conventional water level gauge,demonstrating a vertical array of viewing ports;

FIG. 1 b is a perspective view of an individual port;

FIG. 1 c is a exploded, perspective view of an individual port;

FIGS. 2 a, 2 b, and 2 c constitute a perspective view of a systemaccording to an embodiment of the present invention including thecomponent parts from left to right: namely a level display, a levelgauge, and an illuminator;

FIG. 3 a is an exploded, perspective view of an illuminator according toan embodiment of the present invention;

FIG. 3 b is a completed, perspective view of the illuminator of FIG. 3a;

FIG. 3 c is an exploded, perspective view of an electronics dividerboard, and a lens divider board according to an embodiment of thepresent invention;

FIG. 3 d is a perspective view of the lens divider board of FIG. 3 c,including an array of lenses, one lens of which if presented in anexploded view;

FIG. 3 e is an exploded perspective view of external housing of theilluminator according to an embodiment of the present invention;

FIG. 4 a is a perspective view of an inner display end plate accordingto an embodiment of the present invention;

FIG. 4 b is an exploded, perspective view of a level display accordingto an embodiment of the present invention; and

FIG. 4 c is a completed, perspective view of the level display of FIG. 4b.

FIG. 5 is an exploded, perspective view of a level display according toa second embodiment of the present invention; and

FIG. 6 is a completed, perspective view of the level display of FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

The system of the present invention comprises two main components: anilluminator, and a level display.

These two main components interact with a conventional water level gauge22 as can be seen in FIG. 1A. A conventional water level gauge 22 ismade up of a series of ports 3, arranged vertically along a column 2,each comprising an opening 4 protected by glass, though which light maypass. When installed on a water boiler, or similar device, water orsteam or a combination of the two will pass from the boiler, through thepipe 1, and into the column 2. An operator, who wishes to inspect thecolumn 2 may peer through the series of ports 3, and determine the levelof water within the gauge, and correspondingly, the boiler.

As can be seen in FIGS. 2 a, 2 b, and 2 c, an illuminator 14 and leveldisplay 23 interact with a level gauge 22 by an interface that is formedbetween hooks 18 on the outer housings of the illuminator and the leveldisplay and a bolt 17 on the column 2 of the level gauge.

Referring to FIGS. 3 a–3 e, the illuminator may comprise an electronicprinted circuit board (PCB) 10 containing an array of red and greenlight emitting diodes (LEDs) 19, an array of plano-convex lenses 13,equal in number to the number of LEDs 19, and an external housing 20,made up of a first portion 8 and a second portion 9, adapted forattachment to a conventional water level gauge. The PCB 10 utilizesprecision resistors to regulate the current supplied to each LED 19. ThePCB further utilizes a terminal block corresponding to each LED 19 thatprovides a connection point for the input power and allows for jumperingbetween individual PCBs 10. The PCB 10 is mounted on an electronicsdivider 11 which is, in turn, attached to the first portion 8 and secondportion 9 of the external housing. A lens divider board 12 is positionedadjacent to the array of LEDs 19, and is attached to the first andsecond portions 8,9 of the outer housing. This lens divider board 12,has a number of plano-convex lenses 13, equal to the number of LEDs 19present on the PCB 10. These lenses 13 focus light through an equalnumber of holes 21 in a heat divider 26 on the first portion 8 of theexternal housing so as to provide light to be passed through a levelgauge.

The first and second portions 8,9 of the illuminator further comprise anarray of offset slots 24 extending substantially completely from top tobottom. These slots 24 are designed and offset to limit the transmissionof heat originating in the level gauge. The typical operatingenvironment of a level gauge for a steam boiler is very high, typicallyin the range of 696 degrees F. (369 degrees Celsius). By introducingthese slots to the design, heat transmission by conduction from thelevel gauge to the PCB board assembly and the LEDs is reduced, and theLEDs are isolated from these high operating temperatures.

Referring now to FIGS. 4 a, 4 b, and 4 c, the level display 23 maycomprise a viewing screen 15 for viewing the light transmitted from theLEDs, having passed through a conventional water level gauge, anadjustable end plate 5 for blocking the unused red and green images, anda first portion 16 and second portion 7 of an external housing adaptedfor attachment to a conventional water level gauge. An adjustable endplate 5 provides openings 6 at the levels of concern and blocks thedisplay of unwanted red and green light. The adjustable end plate 5ensures that the operator can clearly distinguish between the levels andreduces error.

Referring now to FIGS. 5, and 6, a second heat divider 25 is providedfor reducing the transmission of heat from the level gauge 22 to theview screen 15. Additionally, an array of offset slots 24 extendssubstantially completely from top to bottom of the level display 23.These slots 24 are designed and offset to limit the transmission ofexcess heat originating in the level gauge 22, which may impair thefunctionality of the display.

INDUSTRIAL APPLICABILITY

The bi-colour water level gauge and illuminator device taught hereingenerally provides an improved means for determining the water level ina boiler steam drum, heater, or similar water/steam device.

1. A bi-colour water level gauge for use in determining the water levelin a boiler steam drum, heater, or similar water/steam devicecharacterized by: an electronic printed circuit board (10) containing anarray of high-intensity narrow beam first colour and second colour lightemitting diodes (19); said electronic printed circuit board (10) beingmounted on an electronics divider board (11); a lens divider board (12)comprising a plurality of viewing ports, each of said ports containingmeans, such as a plano-convex lens (13), for focussing light originatingfrom said light emitting diodes (19), said ports being equal in numberto, and aligned with said light emitting diodes (19); a heat divider(26) for separating said printed circuit board (10) from exposure tohigh temperatures existing at an external housing; and a display means(15) onto which light originating from the light emitting diodes (19) isprojected for inspection by an operator.
 2. A bi-colour water levelgauge for use in determining the water level in a boiler steam drum,heater, or similar water/steam device characterized by: an electronicprinted circuit board (10) containing an array of high-intensity narrowbeam first colour and second colour light emitting diodes (19); saidelectronic printed circuit board (10) being mounted on an electronicsdivider board (11); a divider board (12) comprising a plurality of portsaligned with said light emitting diodes (19); a heat divider (26) forseparating said printed circuit board (10) from high temperaturesexisting at an external housing; and a display means (15) onto whichlight originating from the light emitting diodes (19) is projected forinspection by an operator.
 3. A bi-colour water level gauge illuminatorfor use in determining the water level in a boiler steam drumcharacterized by: an electronic printed circuit board (10) containing anarray of high-intensity narrow beam first colour and second colour lightemitting diodes (19); said electronic printed circuit board (10) beingmounted on an electronics divider board (11); a lens divider board (12)comprising a plurality of ports, each of said ports containing means,such as a plano-convex lens (13), for focussing light originating fromsaid light emitting diodes (19), equal in number to, and aligned withsaid light emitting diodes (19); and a heat divider (26) for separatingsaid printed circuit board (10) from high temperatures existing at anexternal housing.
 4. A bi-colour water level gauge illuminator for usein determining the water level in a boiler steam drum characterized by:an electronic printed circuit board (10) containing an array ofhigh-intensity narrow beam first colour and second colour light emittingdiodes (19); said electronic printed circuit board (10) being mounted onan electronics divider board (11); a divider board (12) comprising aplurality of ports aligned with said light emitting diodes (19); and aheat divider (26) for separating said printed circuit board (10) fromhigh temperatures existing at an external housing.
 5. A bi-colour waterlevel gauge for use in determining the water level in a boiler steamdrum, heater, or similar water/steam device according to claim 1,wherein said array of high-intensity narrow beam first colour and secondcolour light emitting diodes (19) comprises at least two light emittingdiodes of said first colour arranged in parallel for independentoperation and at least two light emitting diodes of said second colourarranged in parallel for independent operation.
 6. A bi-colour waterlevel gauge illuminator according to claim 3, wherein said array ofhigh-intensity narrow beam first colour and second colour light emittingdiodes (19) comprises at least two light emitting diodes of said firstcolour arranged in parallel for independent operation and at least twolight emitting diodes of said second colour arranged in parallel forindependent operation.
 7. A bi-colour water level gauge for use indetermining the water level in a boiler steam drum, heater, or similarwater/steam device according to claim 1, wherein said first colour isred.
 8. A bi-colour water level gauge for use in determining the waterlevel in a boiler steam drum, heater, or similar water/steam deviceaccording to claim 1, wherein said second colour is green.
 9. Abi-colour water level gauge illuminator for use in determining the waterlevel in a boiler steam drum, heater, or similar water/steam deviceaccording to claim 3, wherein said first colour is red.
 10. A bi-colourwater level gauge illuminator for use in determining the water level ina boiler steam drum, heater, or similar water/steam device according toclaim 3 wherein said second colour is green.